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UNIVERSITY  OF  ILLINOIS 


Agricultural  Experiment  Station 


BULLETIN  No.  115 


SOIL  IMPROVEMENT  FOR  THE  WORN 
HILL  LANDS  OF  ILLINOIS 

(With  special  reference  to  Southern  Illinois) 


BY  CYRIL,  G.  HOPKINS  AND  J.  E.  READHIMER 


URBANA,  ILLINOIS,  APRIL,  1901 


SUMMARY  OF  BULLETIN  No.    1 1  5 

1.  Large  areas  of  worn  hill  land,  chiefly  in  southern  and  western  Illinois, 
are  becoming  poor  and  unproductive.  Page  431. 

2.  These  soils  are  most  deficient  in  the  element  nitrogen  and  in  humus, 
and,  if  they  would  grow  well,  marked  improvement  could  be  made  by  cloven 
alfalfa,  cowpeas,  or  other  legumes,  provided    the  crop  or  the  manure  made 
from  it  is  plowed  under.  Page  432- 

3.  Most  of  these  hill  lands  are  so  acid,  or  sour,  that  legume  crops,  espe. 
cially  clover  and  alfalfa,  cannot  be  grown  successfully;  but   they  grow  well 
where  the  acidity  has  been   destroyed  by  an    application   of   ground  lime- 
stone. Page  433. 

4.  Where  a  three-year  rotation  of  corn,  wheat  and  clover  (or  cowpeas) 
has  been  grown  in  Johnson  County  the  past  three  years,  the  average  annual 
value  of  the  grain  crop  has  been  $7.75  an  acre  on  untreated  land,  $9.54  an 
acre  where  legumes  have  been  plowed  under,  and  $14.71  an  acre  where  lime- 
stone has  been  applied  and  legumes  plowed  under.  Page  436. 

5.  Ground  limestone  can  now  be  secured  very  cheaply  from  the  Illinois 
State  Penitentiary  at  Menard,  Illinois,  and  also  from  several  other  points  in 
Illinois  and  adjoining  states.  Page  442. 


SOIL  IMPROVEMENT  FOR  THE  WORN  HILL 
LANDS  OF  ILLINOIS 

(With  special  reference  to  Southern  Illinois) 
BY  CYRIL  G.  HOPKINS,  CHIEF  IN  AGRONOMY  AND  CHEMISTRY,  AND  J.  E. 

READHIMER,  SUPERINTENDENT  OF  SOIL  EXPERIMENT  FIELDS 

There  are  large  areas  of  worn  hill  land  in  Illinois  that  were 
once  rich  and  productive  but  are  now  becoming  poor  and  unpro- 
ductive. By  proper  methods  these  lands  can  be  profitably  improved 
at  small  expense. 

These  sloping  hill  lands  are  especially  extensive  in  the  seven 
southernmost  counties  of  Illinois;  also  in  counties  bordering  the 
Mississippi,  Wabash,  and  Illinois  Rivers  and  to  some  extent  along 
other  smaller  streams. 

In  most  respects  these  hill  lands  are  all  very  much  alike  and  cer- 
tain methods  of  soil  improvement  apply  to  all  of  them,  especially 
for  the  so-called  "clay  hills,"  the  soil  of  which,  however,  is  not  clay 
in  the  true  sense,  but  rather  a  silt  soil  consisting  largely  of  silt,  a 
grade  of  soil  particles  intermediate  between  clay  and  sand,  with  only 
a  small  admixture  of  true  plastic  clay. 

As  to  the  composition  of  these  worn  hill  lands,  with  respect  to 
the  essential  and  valuable  elements  of  plant  food,  large  numbers  of 
analyses  have  shown  that  they  are  exceedingly  rich  in  potassium, 
moderately  well  supplied  with  phosphorus,  but  exceedingly  deficient 
in  nitrogen.  They  are  also  very  deficient  in  organic  matter,  or 
humus,  and  in  southern  Illinois,  especially,  these  soils  are  acid  or 
sour  and  consequently  deficient  in  lime. 

For  the  improvement  of  these  soils  they  should  be  treated  with 
some  form  of  lime  (as  ground  limestone),  and  then  legume  crops 
should  be  grown  frequently  in  rotations  to  be  plowed  under  as 
green  manures  or  fed  to  live  stock  and  returned  to  the  soil  in 
farm  manure.  The  limestone  will  help  especially  the  clover  crop 
and  this  use  of  clover,  cowpeas,  soybeans,  alfalfa,  and  other  legume 
crops  which  have  power  to  secure  nitrogen  from  the  air  (a  power 
not  possessed  by  other  crops)  will  add  nitrogen  to  the  soil  and  also 
restore  the  humus,  or  organic  matter,  which  will  help  to  prevent 

431 


432  BULLETIN  No.  115.  .  [April, 

surface  washing ;  and,  as  it  rots,  or  decays,  in  contact  with  the  soil, 
this  fermenting  organic  matter  will  tend  to  dissolve  and  liberate 
from  the  soil  the  phosphorus  and  potassium  needed  for  the  growth 
of  crops. 

These  lands  should  be  kept  in  meadow  and  pasture  at  least  half 
of  the  time,  and  if  they  are  too  rolling  they  should  be  plowed  up 
only  once  in  eight  or  ten  years  to  give  an  opportunity  to  repeat  the 
limestone  application  and  work  it  well  into  the  soil.  After  one 
crop  of  corn  and  one  or  two  small  grain  crops,  they  should  be 
seeded  down  again  for  meadow  and  pasture,  using  a  mixture  of 
red  clover,  alsike  clover  (which  lives  longer  than  red  clover),  timo- 
thy, and  a  little  red  top. 

The  following  record  of  investigations,  including  pot  cultures 
and  field  experiments,  will  show  the  actual  results  already  obtained 
in  the  improvement  of  these  soils. 

THE;  VIENNA  EXPERIMENT  FIELD 

The  Vienna  soil  experiment  field  is  located  on  worn  hill  land 
about  one  mile  southeast  of  Vienna,  Johnson  County,  on  the  farm 
of  Mr.  J.  M.  Price.  The  soil  on  which  the  field  is  located  is  repre- 
sentative of  the  red  silt  loam  hill  land  of  the  unglaciated  area,  com- 
prising the  greater  portion  of  the  seven  southernmost  counties  of 
the  state :  Union,  Johnson,  Pope,  Hardin,  Alexander,  Pulaski,  and 
Massac.  This  type  also  extends  north  into  Jackson,  Williamson, 
Saline,  Gallatin,  and  other  counties.  The  soil  is  yellowish  red  in 
color  and  is  commonly  spoken  of  as  the  red  clay  hill  soil  of 
southern  Illinois.  It  is  most  deficient  in  the  element  nitrogen.  It 
is  somewhat  poor  in  phosphorus,  but  the  total  supply  of  potassium 
is  very  great.  It  is,  as  a  rule,  too  acid  to  grow  clover  successfully. 
It  is  also  very  poor  in  humus,  or  decaying  organic  matter,  so  much 
so  that  not  even  potassium  is  rendered  available  as  rapidly  as  needed 
by  the  growing  crops.  The  land  on  which  the  field  is  located  has 
been  cropped  for  about  seventy-five  years.  It  is  somewhat  rolling 
and  has  surface-washed  to  some  extent  in  places.  It  had  never  had 
any  soil  treatment  so  far  as  can  be  determined.  It  was  badly  run 
down  when  the  Agricultural  Experiment  Station  came  into  posses- 
sion of  it  in  1902. 

PLAN  OF  EXPERIMENTS 

The  field  is  divided  into  three  series  of  five  fifth-acre  plots.  A 
three-year  rotation  of  corn,  cowpeas,  and  wheat  was  followed  for 


D07.'}   -  SOIL  IMPROVEMENT  FOR  WORN  HILL  LANDS.  433 

four  years,  then  changed  to  corn,  wheat,  and  clover.    In  1902,  oats 
were  grown  in  the  place  of  wheat. 

The  soil  treatment  has  been  as  follows : 

Plot  i  of  each  series,  no  treatment  except  as  the  cowpea  stubble 
or  the  second  growth  of  clover  has  been  plowed  under  in  the  regu- 
lar course  of  the  rotation. 

Plot  2,  legume  catch  crops  plowed  under. 

Plot  3,  legumes  plowed  under  and  lime  applied. 

Plot  4,  legume,  lime,  and  phosphorus. 

Plot  5,  legume,  lime,  phosphorus,  and  potassium. 

The  legume  treatment  consists  of  plowing  under  legume  catch 
crops  grown  after  the  wheat  and  in  the  corn  after  the  last  cultiva- 
tion. The  first  three  crops  of  cowpeas  in  the  regular  rotation  were 
also  plowed  under,  one  crop  on  each  of  the  series  on  all  of  the  plots 
except  the  untreated  check  plot,  No.  i.  Since  that  time  the  regular 
cowpea  crops  have  been  harvested  and  removed  from  all  of  the  plots. 

The  primary  object  in  applying  lime  is  to  correct  soil  acidity. 
In  the  spring  of  1902  one  ton  per  acre  of  slacked  lime  was  applied; 
but,  a  method  having  been  worked  out  by  which  we  were  able  to 
determine  by  chemical  analysis  how  much  lime  is  equivalent  to  the 
soil  acidity  to  any  depth,  it  was  found  that  the  soil  on  this  field  was 
acid  in  the  surface,  more  acid  in  the  subsurface,  and  still  more  acid 
in  the  subsoil,  and  in  order  to  provide  ample  lime  to  correct  this 
acidity  an  additional  application  of  eight  tons  per  acre  of  ground 
limestone  was  made  in  the  fall  of  1902.  While  the  lime  does  not 
descend  into  the  subsoil  in  appreciable  amounts,  some  acidity  from 
the  subsoil  may  be  brought  to  the  surface  in  capillary  moisture 
Further  investigations  are  in  progress  relating  to  the  liming  of 
soils,  but  from  all  information  now  available  it  is  believed  that  two 
to  four  tons  per  acre  of  ground  limestone  as  an  initial  application 
will  give  very  satisfactory  results.  Heavier  applications  may  pos- 
sibly give  more  profit  per  acre,  but  less  profit  per  ton  of  limestone 
used. 

Phosphorus  has  been  applied  at  the  rate  of  25  pounds,  and 
potassium  at  the  rate  of  40  pounds,  per  acre  per  annum,  the  pres- 
ent regular  practice  being  to  apply  once  in  three  years  600  pounds 
of  steamed  bone  meal,  containing  12^/2  percent  phosphorus,  and 
300  pounds  of  potassium  sulfate,  containing  40  percent  of  potas- 
sium. 

Four  crops  of  wheat,  one  of  oats,  five  of  corn  and  five  of  cow- 
peas  have  been  grown  on  the  field  since  the  work  was  begun  in 
1902.  The  yields  of  wheat  and  oats  are  given  in  Table  i. 


434  BULLETIN  No.  115.  [April, 

TABLE  1.— CROP  YIELDS  PROM  VIENNA  SOIL  EXPERIMENT  FIELD 


Soil 
plot 
Nos. 

Red  silt 
loam  hill 
land  of  the 
unglaciated 
area. 

Bushels  per  acre. 

1902 
Oats, 
series 
200. 

1903 
Wheat, 
series 
300. 

1904 
Wheat, 
series 
200. 

1905 
Wheat, 
series 
100. 

1906 
Wheat, 
series 
200. 

Total 
from 
last  3 
crops. 

Treatment 
applied. 

Total 
yield. 

Total 
yield. 

Total 
yield. 

Total 
yield. 

Total 
yield. 

Wheat, 
bu. 

1 

None  

19.1 

.4 

6.7 

1.3 

3.8 

11.8    . 

2 

Legume  

18.8 

.6 

7.1 

10.8 

5.4 

23.3 

3 

Legume,  lime. 

19.8 

.7 

10.0 

18.2 

17.9 

46.1 

'•4  ' 

Legume,  lime, 
phosphorus. 

20.0 

8.0 

14.8 

25.6 

11.3 

51.7 

5 

Legume,  lime, 
phosphorus, 
potassium  .  . 

31.7 

11.0 

17.5 

30.0 

15.0 

58.7 

In  1903  the  wheat  crop  was  almost  a  failure  in  this  section  of 
the  state.  The  first  three  plots  produced  less  than  a  bushel  per  acre. 
Plot  4  produced  8  bushels,  while  plot  5  produced  n  bushels,  in- 
dicating that  the  decaying  organic  matter  was  so  deficient  that  the 
phosphorus  and  gotassium  naturally  present  in  the  soil  were  not 
made  available. 

In  1905,  the  yield  was  increased  from  1.3  bushels  on  -the  un- 
treated plot  to  1 8. 2  bushels  on  the  legume-lime  plot,  a  gain  of  16.9 
bushels  per  acre,  due  to  the  plowing  under  of  cowpeas,  which  had 
grown  much  better  where  lime  was  applied.  The  addition  of  phos- 
phorus and  potassium  gave  a  further  increase. 

In  1906,  legume-lime  treatment  increased  the  yield  from  3.8 
bushels  on  the  check  plot  to  17.9  bushels,  an  increase  of  14.1 
bushels.  The  addition  of  phosphorus  and  potassium  produced  no 
increase,  and  the  yields  were  irregular,  for  some  reason  not  yet 
understood. 

By  computing  from  the  total  wheat  yields  for  the  last  three 
years  we  have  the  following  results : 

Untreated  land  produced 11.8  bushels 

Legume  treatment  increased  the  yield 11.5 

Legume-lime  treatment  increased  the  yield 34.3 

Land  with  legume-lime  treatment  produced 46.1 

Phosphorus  treatment  increased  the  yield 5.6 

Potassium  treatment  increased  the  yield 7.0 

It  will  be  seen  that  the  use  of  legume  green  manure  crops  has 
doubled  the  yield  of  wheat  and  that  four  times  as  much  wheat  has 
been  grown  where  legume-lime  treatment  has  been  used  as  on  the 


1907.] 


SOIL  IMPROVEMENT  FOR  WORN  HILL  LANDS. 


435 


untreated  land.  It  should  be  kept  in  mind,  however,  that  the  im- 
portant direct  effect  of  the  lime  (ground  limestone)  is  to  increase 
the  growth  of  the  green  manure  crops. 

The  yields  of  corn  for  the  five  years  are  given  in  Table  2. 

TABLE  2.— CORN  YIELDS  FROM  VIENNA  SOIL  EXPERIMENT  FIELD 


Corn 

,  bushels 

per  acre 

Soil 
plot 
Nos. 

rCea  silt 
loam  hill 
land  of  the 
unglaciated 
area. 

1902 
Series 
100. 

1903 
Series 
100. 

1904 
Series 
300. 

1905 
Series 
200. 

1906 
Series 
300. 

Total 
from 
Iast3 
crops. 

.  Treatment 

Total 

Total 

Total 

Total 

Total 

Corn, 

applied. 

yield. 

yield. 

yield. 

yield. 

yield. 

bu. 

1 

None  

15.5 

9.3 

30.5 

37.5 

41.2 

109.2 

2 

Lesrume.  . 

13.3 

5.0 

35.5 

42.9 

40.6 

117.0 

3 

Legume,  lime. 

14.9 

8.3 

49.1 

61.9 

48.9 

159.9 

4. 

Legume,  lime 

phosphorus  . 

12.5 

7.4 

49.4 

57.2 

40.9 

147.5 

Legume,  lime 

5 

phosphorus 

potassium  . 

19.9 

11.6 

44.7 

56.5 

40.9 

142.1 

We  see  from  Table  2  that  the  yields  of  corn  were  small  in  1902 
and  1903.  This  was  partly  due  to  the  dry  weather,  and  partly  due 
to  the  lack  of  available  plant  food,  there  having  been  no  previous 
legume  treatment  for  the  1902  corn  crop  and  but  a  light  catch  crop 
of  cowpeas  grown  in  1902  for  the  1903  corn  crop.  The  yields 
were  much  larger  in  1904,  1905,  and  1906  because  there  had  been 
more  nitrogen  and  decaying  organic  matter  added  to  the  soil 
through  the  turning  under  of  cowpeas  which  usually  made  a  good 
growth  where  lime  had  been  applied,  and  the  seasons  were  better. 

By  adding  the  results  for  the  last  three  years  we  have  the  fol- 
lowing significant  figures : 

The  untreated  land  produced 109.2  bushels 

Legume  treatment  alone  increased  the  yield  only.       7.8        " 
Legume-lime  treatment  increased  the  yield 50.7         " 

Neither  phosphorus  nor  potassium  increased  the  yield  of  corn 
beyond  that  produced  by  legume-lime  treatment.  In  some  cases 
the  yields  are  even  lower  where  these  elements  were  applied.  This 
is  doubtless  due  to  natural  differences  in  these  plots,  Nos.  4  and  5 
being  more  subject  to  surface  washing  than  Nos.  I,  2,  and  3.  (It 
is  the  regular  plan  to  put  the  untreated  check  plots  on  the  best  land 
and  the  best  treated  plots  on  the  poorest  land,  if  any  natural  dif- 
ferences exist  in  the  field.) 


36  BULLETIN  No.  115.  [April, 

While  some  gains  have  heen  made  on  wheat  and  corn  by  legume 
treatment  without  lime,  the  most  marked  and  by  far  the  most  profit- 
able gains  have  been  made  where  lime  (ground  limestone)  has 
been  used  in  connection  with  the  legume  green  manures.  At  70 
cents  a  bushel  for  wheat  and  35  cents  a  bushel  for  corn,  the  value 
of  the  increase  produced  by  lime  as  an  average  of  the  years  1904, 
1905,  and  1906,  has  been  $5.32  an  acre  for  wheat  and  $5.01  for 
corn.  These  amounts  would  pay  5  percent  interest  on  more  than 
$100,  which  is  five  to  ten  times  as  much  as  would  be  needed  to 
make  a  heavy  initial  application  of  ground  limestone. 

POT  CULTURE  EXPERIMENTS  ON  UNGLACIATED  HILL  LAND 

Some  very  instructive  results  have  been  obtained  from  a  series 
of  pot  culture  experiments  which  have  been  in  progress  since  1902 
in  the  pot  culture  greenhouse,  and  in  which  this  red  silt  loam  of 
the  unglaciated  hill  land  has  been  used.  The  soil  was  collected  by 
Mr.  W.  O.  Farrin  in  the  fall  of  1901  and  represents  the  old  worn 
hill  soil  of  Pulaski  County.  It  is  much  poorer  in  nitrogen  and 
humus  than  the  average  of  the  type,  although  large  areas  are  to  be 
found  as  badly  worn  as  the  field  from  which  this  soil  was  collected. 
This  field  has  been  under  cultivation  for  about  seventy-five  years 
and  was  still  being  cropped  when  the  soil  was  collected.  During 
the  earlier  period  of  its  cultivation  the  soil  frequently  produced 
25  bushels  of  wheat  an  acre,  but  during  the  later  years  about  5 
bushels  has  been  the  average  crop  in  normal  seasons. 

The  first  year's  work  with  these  pot  cultures  was  performed 
by  Mr.  Farrin  as  a  thesis  for  graduation  from  the  University  of 
Illinois,  College  of  Agriculture,  in  1902. 

Table  3  gives  the  results  of  five  years'  experiments  with  pot 
cultures  on  this  type  of  soil. 

From  a  study  of  Table  3  it  is  seen  that  practically  no  gain  has 
been  made  except  where  nitrogen  was  supplied,  either  directly  in 
commercial  form  or  indirectly  by  means  of  legume  treatment.  It 
should  be  borne  in  mind  that  no  legume  treatment  preceded  the 
1902  wheat  crop.  The  catch  crop  of  cowpeas  which  was  planted 
after  the  1902  wheat  crop  and  turned  under  later  in  the  fall  pro- 
duced a  marked  effect  upon  the  1903  wheat  crop.  This  effect  be- 
came more  marked  in  1904  and  1905  when  every  pot  receiving 
legume  treatment  outyielded  the  pot  receiving  lime-nitrogen  treat- 
ment. Previous  to  1905,  the  addition  of  phosphorus  to  nitrogen 
or  legume  treatment  always  increased  the  yield,  and  the  addition 
of  potassium  still  further  increased  the  yield  after  the  first  year. 


1907.] 


SOIL  IMPROVEMENT  FOR  WORN  HILL  LANDS. 


437 


The  effect  of  both  phosphorus  and  potassium  has  been  less  where 
decaying  organic  matter  has  been  provided  in  the  legume  treatment 
than  where  the  nitrogen  has  been  supplied  in  commercial  form 
carrying  but  little  organic  matter.  Since  1905  there  has  been  prac- 
tically no  effect  from  either  the  phosphorus  or  potassium  when 
added  to  legume  treatment.  When  added  to  commercial  nitrogen, 
however,  they  both  gave  a  substantial  gain  in  yield.  This  condi- 
tion is  doubtless  brought  about  by  the  liberation  of  both  phosphorus 
and  potassium  from  the  soil  by  the  decay  of  the  organic  matter  of 
the  legume. 

The  last  line  in  the  table  gives  the  yields  from  a  pot  of  virgin 
soil  collected  from  a  piece  of  unbroken  virgin  sod  land  adjoining 
the  cultivated  field  from  which  the  soil  in  all  the  other  pots  was 
taken.  It  is  seen  that  the  yields  from  this  pot  are  gradually  de- 
creasing, doubtless  due  to  the  exhaustion  of  the  nitrogen  contained 
in  the  soil. 

TABLE  3. — WHEAT  YIELDS  FROM  PULASKI  COUNTY  SOIL 
(Pot  culture  experiments) 


Red  silt  loam 
hill  land  of  the  un- 
glaciated  area. 

1902 
Wheat, 

1903 
Wheat, 

1904 
Wheat, 

1905 
Wheat, 

1906 
Wheat, 

Total  for 
last  4 
years. 

Soil  treatment 
applied. 

grams. 

grams. 

grams. 

grams. 

grams. 

Wheat, 
grams. 

None  

3 

5 

4 

4 

4 

17 

Legume,  lime  

4 

10 

17 

26 

19 

72 

Legume,  lime,  phos- 
phorus   

3 

14 

19 

20 

18 

71 

Legume,  lime,  phos- 
phorus, potassium 

3 

16 

20 

21 

19 

76 

Lime,  nitrogen  
Lime,  phosphorus.  .  . 
Lime,  potassium  .... 

26 
3 
3 

17 
6 
3 

14 
4 
3 

15 
6 
•5 

9 
4 
5 

55 
20 
16 

Lime,  nitrogen,  phos- 
phorus   

34 

26 

20 

18 

18 

82 

Lime,  nitrogen,  po- 
tassium   

33 

14 

21 

21 

16 

72 

Lime,      phosphorus, 
potassium  

2 

3 

3 

5 

3 

14 

Lime,  nitrogen,  phos- 
phorus, potassium 

Virgin  soil  (no  treat- 
f-  ment)  

34 
24 

31 
17 

34 
15 

21 
17 

20 
13 

106 
62 

438  BULLETIN  No.  115.  [April, 

The  results  from  the  pot  cultures  bear  out  very  conclusively  the 
results  obtained  from  the  field  tests;  namely,  that  marked  im- 
provement can  be  made  on  this  soil  by  turning  under  legume  crops 
where  lime  has  been  applied. 

Another  series  of  pot  culture  experiments,  with  soil  from  the 
worn  hill  lands  of  Henry  County,  in  northwestern  Illinois,  carried 
on  at  the  university  by  Mr.  I.  D.  Allison,  under  the  direction  of 
the  Agricultural  Experiment  Station,  furnishes  additional  informa- 
tion concerning  the  great  need  of  nitrogen  for  these  hill  lands. 

The  plan  of  these  experiments,  the  soil  treatment  applied,  and 
the  results  obtained  are  all  shown  in  Table  4. 

TABLE  4.— OAT  YIELDS  FROM  HENRY  COUNTY  SOIL 
(Pot  culture  experiments) 


Gray  silt  loam  hill  land 
Upper  Illinois  Glaciation. 

Oat 

yields, 

Soil  treatment  applied. 

grams  per  pot. 

None  

5 

Lime  

4 

Lime,  nitrogen  

45 

Lime,  phosphorus  

6 

Lime,  potassium  

5 

Lime,  nitrogen,  phosphorus  

QS 

Lime,  nitrogen,  potassium  

4fi 

Lime,  phosphorus,  potassium  

5. 

Lime,  nitrogen,  phosphorus,  potassium  .... 
Nitrogen,  phosphorus,  potassium  

38 
31 

None  

5 

It  will  be  seen  that  the  yield  of  oats  was  increased  from  about 
5  to  40  by  the  addition  of  nitrogen.  In  other  words,  where  nitro- 
gen was  applied  the  yield  of  oats  was  about  eight  times  as  large  as 
where  no  nitrogen  was  applied  to  the  soil. 

No  definite  effect  can  be  seen  from  the  use  of  phosphoru's  or 
potassium.  The  application  of  lime  alone  without  nitrogen  pro- 
duced no  benefit,  but  it  is  noteworthy,  perhaps,  that  the  lowest  yield 
obtained  with  nitrogen  added  was  where  lime  was  omitted,  thus 
indicating  that  lime  and  nitrogen  together  are  best  for  this  soil. 
This  means,  of  course,  that  if  the  soil  is  sour,  lime  should  be  ap- 
plied, and  then  legume  crops  should  be  grown  to  get  nitrogen  from 
the  air,  these  crops  to  be  plowed  under  either  directly  or  in  farm 
manure. 


1907.}  SOIL  IMPROVEMENT  FOR  WORN  HILL  LANDS.  439 

CROP  ROTATIONS 

The  methods  employed  by  which  the  most  profitable  results 
given  in  Tables  i  and  2  have  been  obtained  consist  of  crop  rotation r 
in  which  a  legume  has  been  grown  every  third  year  in  the  regular 
rotation  and  also  legume  catch  crops,  as  cowpeas,  planted  after  the 
wheat  and  in  the  corn  to  supply  the  humus  and  nitrogen  so  badly 
needed ;  also  the  addition  of  sufficient  lime  to  correct  the  acidity  of 
the  soil  in  order  to  encourage  the  development  and  activity  of  the 
nitrogen-fixing  and  nitrifying  bacteria.  The  rotation  practiced  on 
this  soil  experiment  field  has  been  a  three-course  system  of  cornr 
wheat,  and  legume,  with  catch  crops  of  legumes  after  the  wheat 
and  in  the  corn  at  the  time  of  the  last  cultivation.  A  longer  rota- 
tion of  six  years  is  even  better  adapted  to  the  worn  hill  lands  of 
southern  Illinois.  The  following  is  suggested: 

First  year,  corn 

Second  year,  cowpeas  or  soybeans 

Third  year,  wheat 

Fourth  year,  clover  and  timothy  meadow 

Fifth  year,  pasture 

Sixth  year,  pasture 

A  legume  catch  crop  should  be  planted  in  the  corn  at  the  last 
cultivation.  For  this  purpose  cowpeas  serve  very  well,  but  some 
results  already  obtained  in  other  experiments  indicate  that  ordinary 
sweet  clover  (melilotus  alba)  will  be  of  very  much  greater  value. 
This  may  be  allowed  to  stand  over  winter  and  make  a  large  growth 
before  being  plowed  under  in  the  late  spring  and  before  planting  the 
regular  cowpea  crop. 

If  sweet  clover  is  to  be  seeded  the  land  should  be  inoculated 
by  scattering  a  few  hundred  pounds  to  the  acre  of  infected  soil  col- 
lected from  old  alfalfa  land  or  from  a  patch  of  sweet  clover  which 
is  well  provided  with  root  tubercles. 

In  practicing  a  six-year  rotation  the  farm  should  be  divided  into 
six  nearly  equal  fields  so  that  every  crop  may  be  grown  every  year. 
Thus,  on  a  i2O-acre  farm  there  would  be  20  acres  of  corn,  20  acres 
of  cowpeas  or  soybeans,  20  acres  of  wheat,  20  acres  of  clover,  and 
two  2o-acre  pastures,  and  every  year  there  should  be  20  acres  of 
second-year  pasture  ground  to  be  plowed  for  corn,  and  20  acres  of 
cowpea  or  soybean  ground  to  be  seeded  to  wheat.  If  any  crop  fails 
some  other  similar  crop  should  be  substituted  which  will  not  seri- 
ously interfere  with  the  rotation.  Thus,  if  wheat  winter-kills,  oats 
may  be  seeded  in  the  spring  and  the  clover  seeded  with  the  oats. 


440  BULLETIN  No.  115.  [April, 

THE  USE  OF  THE  CROPS 

The  wheat  should  be  sold  and  also  the  clover  seed  if  not 
needed  for  home  use.  Some  cowpea  or  soybean  seed  and  some 
corn  may  also  be  sold,  but  all  forage,  hay,  corn  stover,  and  wheat 
or  oat  straw,  and  most  of  the  corn  should  be  fed  on  the  farm, 
plenty  of  bedding  being  used  and  all  manure  carefully  returned  to 
the  land,  preferably  as  soon  as  possible  after  being  made.  It  may 
be  spread  on  the  meadow  or  pasture  land  which  is  to  be  plowed 
for  corn.  If  desirable,  the  cowpea  or  soybean  crop  may  largely  be 
"hogged"  off,  thus  getting  the  benefit  of  the  seed,  while  the  vines 
and  the  manure  dropped  by  the  hogs  are  left  on  the  land  to  enrich 
it  for  the  wheat  crop.  If  there  is  permanent  pasture  on  the  farm, 
this  rotation  may  be  reduced  to  the  first  four  years. 

THE  USE  OF  LIMESTONE 

The  old  worn  hill  soils  of  the  unglaciated  area  are  markedly 
acid  and  farmers  find  it  difficult  to  grow  clover  successfully  on 
them.  At  least  two  tons  to  the  acre  of  ground  limestone  should 
be  applied  as  an  initial  application.  Afterward  one  ton  to  the  acre 
every  four  to  six  years  will  probably  be  sufficient  to  keep  the  soil 
sweet. 

There  is  no  danger  of  applying  too  much  ground  limestone. 
The  Agricultural  Experiment  Station  of  Illinois  has  applied  as  high 
as  10  tons  per  acre  with  only  good  results;  and  the  Rothamsted 
(England)  Experiment  Station  reports  applications  of  chalk  equiv- 
alent to  100  tons  per  acre  of  ground  limestone,  and  the  soil  remains 
very  productive.  It  is  well  known  that  natural  limestone  soils  are 
both  productive  and  durable. 

From  two  to  four  tons  per  acre  of  ground  limestone  should  be 
sufficient  to  give  profitable  returns,  although  four  to  eight  tons  per 
acre  might  give  better  and  more  profitable  returns  per  acre,  but 
probably  less  profit  per  ton  than  the  lighter  application,  Any  other 
form  of  lime  may  be  used  in  place  of  limestone  if  it  can  be  obtained 
more  cheaply,  provided  an  ample  supply  of  organic  matter  is  main- 
tained in  the  soil. 

The  limestone  may  be  applied  at  any  time  when  it  can  be  hauled 
and  spread.  It  will  not  give  the  best  results  till  it  becomes  well 
mixed  with  the  plowed  soil. 

It  has  been  proved  that  alfalfa  will  not  grow  successfully  on  the 
worn  hill  lands  of  southern  Illinois  without  lime,  but  that  it  grows 
luxuriantly  where  the  land  has  first  been  well  limed. 


1907.1  SOIL  IMPROVEMENT  FOR  WORN  HILL  LANDS.  441 

THE  USE  OE  PHOSPHORUS 

While  phosphorus  has  produced  some  marked  results  on  the 
wheat  crop,  it  has  not  as  yet  increased  the  yield  of  corn,  and  has 
not  been  used  with  profit  in  the  rotation. 

It  is  very  probable  that  after  the  land  has  been  much  improved 
with  the  use  of  lime  and  the  turning  under  of  legume  crops  and 
manures  and  other  organic  matter,  then  we  may  be  able  to  use 
phosphorus  with  profit  to  increase  still  further  the  crop  yields ;  but 
further  investigation  is  needed  to  determine  this. 

It  should  be  remembered  that  even  where  we  try  to  prevent 
surface-washing  by  very  deep  plowing,  by  use  of  winter  cover 
crops,  and  by  keeping  the  land  in  pasture  much  of  the  time,  there 
is  still  some  loss  of  surface  soil  from  rolling  land.  This  brings 
new  supplies  of  phosphorus  within  reach  of  the  feeding  roots  of 
plants;  so  that  a  system  of  permanent  agriculture  (of  low  grade 
at  least)  is  possible  on  these  soils  without  the  return  of  phosphorus. 

THE  USE  OE  POTASSIUM 

As  was  stated  in  the  beginning,  the  total  supply  of  potassium 
in  these  soils  is  very  great.  Still  the  application  of  potassium  has 
always  produced  an  effect  on  the  wheat  crop.  This  is  possibly 
due  to  the  stimulating  or  corrosive  effect  of  the  potassium  salt  in 
liberating  other  plant  food  elements,  as  nitrogen  and  phosphorus, 
rather  than  the  direct  effect  of  the  element  as  plant  food.  It  will 
be  noted  that  as  the  supply  of  organic  matter  is  increased  in  the 
soil  the  effect  of  potassium  is  less  and  less  marked.  Where  the  sup- 
ply of  potassium  in  the  first  seven  inches  of  the  soil  is  sufficient  to 
produce  two  thousand  forty-bushel  crops  of  wheat,  it  would  seem 
unnecessary  to  apply  it  to  the  land.  We  believe  that  when  more 
decaying  organic  matter  has  been  worked  into  the  soil  all  of  the 
potassium  that  is  necessary  for  the  growth  of  maximum  crops  will 
be  made  available.  We,  therefore,  do  not  recommend  the  use  of 
potassium  on  these  soils. 

PERMANENT  SYSTEMS 

We  should  allow  50  cents  an  acre  a  year  for  ground  limestone, 
after  the  heavy  initial  application  has  been  made  (the  cost  of  which 
should  be  added  to  the  value  of  the  land),  one  ton  costing  about 
$1.00  to  $2.00  delivered  in  carload  lots  at  most  railroad  stations  in 
southern  or  western  Illinois.  It  is  assumed  that  the  seed  for  legume 
catch  crops  will  be  raised  on  the  farm,  and  in  some  cases,  as  with 


442  BULLETIN  No.  115.  [April, 

cowpeas  or  soybeans,  the  pasturing  of  such  crops  may  pay  for  seed 
and  seeding. 

As  a  rule,  the  greatest  difficulty  to  be  overcome  in  the  introduc- 
tion of  a  more  intensive  system  of  agriculture,  by  which  larger 
crops  and  greater  profits  are  to  be  made,  is  for  the  farmer  to  per- 
suade himself  to  hold  fast  to  a  good  rotation  of  crops  and  to  con- 
tinue to  make  good  use  of  all  obtainable  farm  manure,  by  which 
means  alone  can  he  hope  to  maintain  sufficient  nitrogen  and  humus 
in  the  soil. 

Neither  ground  limestone,  nor  steamed  bone  meal,  nor  raw 
natural  rock  phosphate  will  ever  injure  the  land,  but  the  benefit  to 
be  derived  from  the  use  of  those  materials  alone  is  temporary  in 
continuous  grain  growing,  and  no  profitable  and  permanent  sys- 
tem of  agriculture  can  be  adopted  for  Illinois  which  does  not  in- 
clude a  rotation  of  crops  with  a  liberal  use  of  legumes,  and  it  is 
exceedingly  good  practice  to  make  and  use  as  much  farm  manure 
as  possible. 

APPLICATION  OF  LIMESTONE 

It  makes  no  great  difference  as  to  when  or  how  we  apply  such 
materials  as  ground  limestone,  rock  phosphate,  or  steamed  bone 
meal,  except  that  they  must  be  well  mixed  with  the  soil  before  the 
best  results  can  be  secured,  consequently  there  is  likely  to  be  less 
benefit  the  first  year  than  in  later  years. 

Probably  one  cannot  do  better  than  to  apply  limestone  on  newly 
plowed  land  in  August  or  September,  to  be  mixed  with  the  soil  by 
disking,  harrowing,  etc.,  in  preparing  the  ground  for  wheat  where 
clover  is  to  be  seeded  the  next  spring. 

Steamed  bone  meal  is  commonly  drilled  in  with  the  wheat,  but, 
if  rock  phosphate  is  used,  it  should  be  plowed  under  with  manure 
or  clover  or  other  decaying  organic  matter. 

For  much  further  information  concerning  the  methods  of  apply- 
ing limestone,  including  directions  for  making  a  limestone  spreader, 
comparative  value  of  burned  lime,  slacked  lime,  and  ground  lime- 
stone, see  Illinois  Circular  no,  "Ground  Limestone  for  Acid  Soils." 

This  will  be  sent  free  of  charge  upon  application  to  Director  E. 
Davenport,  Agricultural*  Experiment  Station,  Urbana,  Illinois ;  and 
if  requested  the  applicant's  name  will  be  placed  upon  the  permanent 
mailing  list  for  subsequent  publications. 


1907. J  SOIL  IMPROVEMENT  FOR  WORN  HILL  LANDS.  443 

Notes.— Ground  limestone  now  can  be  obtained  at  75  cents  a  ton  from  the 
Southern  Illinois  Penitentiary,  Menard,  111. ,  and  at  different  prices  from  Cas- 
per Stolle Quarry  &  Contracting  Co.,  St.  Louis,  Mo.,  (quarry  at  Stolle,  111.); 
Southwestern  Contracting  &  Engineering-  Co.,  East  St.  Louis,  111.;  Crystal 
Carbonate  Lime  Company,  Ellsberry,  Mo.;  Carthage  Superior  Limestone 
Co.,  Carthage,  Mo.;  Mitchell  Lime  Company,  Mitchell,  Ind.  Some  of  these 
companies  furnish  fine  ground  limestone  and  some  furnish  limestone  screen- 
ings, which  include  both  very  fine  dust  and  some  coarser  particles,  even 
as  large  as  wheat  grains.  In  carload  lots  the  price  on  board  cars  at  the 
plant  varies  from  50  cents  to  $1.00  a  ton,  accorc  ing  to  the  fineness.  The 
freight  charges  will  vary  from  50  cents  or  less  to  $1.50  or  more,  depending 
upon  the  distance.  At  most  points  in  Illinois  the  cost  delivered  in  bulk  in 
box  cars  should  be  between  $1X0  and  $2.00  a  ton.  The  quickest  action  will 
be  secured  by  using  the  finest  material  and  mixing  it  most  thoroughly  with 
the  soil,  but  sometimes  one  can  get  one  and  one-half  tons  of  material  con- 
taining one  ton  of  fine  dust  and  half  a  ton  of  coarser  particles,  varying  in 
size  from  less  than  pin  heads  to  wheat  grains,  at  no  greater  expense  than 
would  be  required  for  one  ton  of  fine  ground  stone  containing  no  coarser 
particles. 

Finely  ground  raw  rock  phosphate  (12%  percent  phosphorus)  can  be 
obtained  from  Robin  Jones,  Nashville,  Tenn.,  or  from  the  N.  Y.  &  St.  L. 
Mining  &  Mfg.  Co.,  St.  Louis,  Mo.,  delivered  in  carload  lots  for  about  $8.00 
a  ton  in  southern  Illinois,  the  cost  being  $1.00  to  $2.00  higher  for  central 
and  northern  Illinois  points. 

A  good  grade  of  steamed  bone  meal  (about  12%  percent  phosphorus) 
can  be  obtained  delivered  in  Illinois  for  about  $25.00  a  ton,  from  the  local 
agents  of  Morris  &  Co.,  Swift  &  Co.,  or  the  Packers  Fertilizer  Association, 
Chicago,  111.,  or  from  Michigan  Carbon  Works,  Detroit,  Mich. 


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